利用超高效液相色谱-四级杆-飞行时间串联质谱(UPLC-Q-TOF-MS)对8种海洋硅藻的四种主要光合膜膜脂的分子结构和组成进行了定性定量分析。结果表明,海洋硅藻中MGDG含量最高,占四种光合膜膜脂的40%70%左右,SQDG其次占10%40%,而PG在4%20%之间,DGDG占5%20%;其中,各脂类分子的含量在0.1499.79 nmol/mg干藻之间,而C16:3/C16:3-MGDG,C20:5/C16:3-MGDG,C20:5/C16:2-DGDG,C20:5/C16:1-DGDG,C16:1/C16:1-DGDG,C14:0/C14:0-SQDG,C14:0/C16:0-SQDG,C14:0/16:1-SQDG,C14:0/C16:3-SQDG和C18:1/C18:1-PG等脂类分子在8种海洋硅藻的每一类膜脂中均有分布;与高等植物膜脂的脂肪酰基分布不同的是,海洋硅藻的MGDG与DGDG的sn-2位上的脂肪酸全部为C16酸,可推断是通过类似高等植物典型的原核途径合成,而C16酸和C18酸在SQDG和PG的sn-2位上均有分布,可推断SQDG和PG存在原核和真核两种合...更多成途径。 还原
In this work,an exhaustive qualitative and quantitative profiling of the photosynthetic glycerolipids fraction of the 8 microalga diatoms was carried by Ultra Performance Liquid Chromatography-Electrospray ionization-Quadrupole-Time of Flight Mass Spectrometry(UPLC-ESI-Q-TOF-MS).In the diatom thylakoids membrane,monogalactosyldiacylglycerol(MGDG) and digalactosyldiacylglycerol(DGDG) account for about 40%~70% and 5%~20% of the total membrane lipids,respectively.The anionic sulfoquinovosyldiacylglycerol(SQDG) as well as the likewise anionic phosphatidylglycerol(PG) contribute between 10%~40% and 4%~20% each.In the 8 diatoms,the molecular species of photosynthetic glycerolipids had been determined with content ranged from 0.14 to 99.79 nmol/mg dry weight.The predominant species of MGDG were those with C16:3/C16:3 and C20:5/C16:3;Three main molecular species of DGDG in the 8 diatoms always contained C20:5/C16:1,C20:5/C16:2 and C16:1/C16:1;The major molecular species of SQDG were those containing combinations of C14:0/C14:0,C14:0/C16:0,C14:0/16:1 and C14:0/C16:3.;All the PG classes contained the C18:1/C18:1 as the main molecular species.The data also indicated that MGDG and DGDG are biosynthesized through prokaryotic pathway exclusively within the chloroplast,because all the fatty acids linked at sn-2 position are several C16 fatty acids in MGDG and DGDG.On the other hand,PG and SQDG have a typical mixed biosynthetic pathway(both prokaryotic pathway and eukaryotic pathway) because the fatty acids at sn-2 position include both C16 and C18 fatty acids.